Tiled 1.8.1

Changelog

• Fixed pasted objects not getting selected if a tile layer was also copied
• Fixed possible crash when trying to determine whether OpenGL is used
• Fixed possible crash when using the Insert Tile tool
• Fixed possible crash in tile stamp preview
• AutoMapping: Fixed crash when an input layer does not exist (#3269)
• Scripting: Automatically add tilesets to the map where needed (#3268)
• snap: Updated from core18 to core20 (now uses Qt 5.12)
• AppImage: Updated to Sentry 0.4.15